A circuit for power amplification of an input signal includes an input stage and an output stage, the said input stage including: a drive means incorporating a so-called main drive transistor, and a first so-called main input transistor able to receive the input signal, and mounted as a current mirror with the main drive transistor The first main input transistor is coupled to the output stage via a second so-called main input transistor incorporated into the input stage and controlled by the drive means, the first and second main input transistors being coupled together and with the earth according to a structure of Darlington type by way of a resonant circuit